If you send me images, I'll be happy to take a look at them.

whiteflies. I hate them. google insecticidal soap. dr bronners does the trick very well.

That does appear to be the Adelgid and if there are not enough natural predators to control them a sharp spray of water that knocks them off the tree can help.

A lot of what you are seeing depends on the crop and the weather conditions. So you'll see smaller tighter heads in cooler weather and lots more green leafy heads in warmer weather. Don't know how long it takes to get the lettuce to your market, but it's highly perishable, so the heads will look different all the time. And if the heads are too bushy and the outer leaves get damaged, then the outer leaves are trimmed for the bags of "hearts". The new crop here in the Salinas Valley is just going in, and the workers are starting to return from Arizona and the Imperial Valley.